Frank,
Here's how I test Lucas generator systems. I learned this when I went to
BMC tech school while I was working at Shore Motors, and you know how many
years ago that was.... I think the Lucas Boys were still perfecting the
automatic flicker and dim switch back then......
1 Pull the D and F terminals from the generator.
2. Jumper the D and F terminals together with a short jumper
3. With the neg (or POS for - ground cars) lead of a NON-DIGITAL voltmeter
clipped to either terminal, and the other lead grounded, start the engine.
Don';t rev it above 1000. Quickly, bring the eng to about 1000 revs, and
you should read about 16 or 17 volts after just a second or two. DON;T REV
the engine above 1100 and don;t let it run longer than whatever it takes to
get the voltage reading, because an unregulated generator will get mighty hot
in a hurry.... In fact, I use a normally open spring loaded switch between
the generator terminal jumper to break the circuit as soon as possible.
If the voltage sits at about 5 - 6 volts, then the problem is usu
broken down windings, or cold solder joints where the windings and brushes
are connected. If you get less than 2 or 3 volts, the brushes are bad or the
commutator is greasy or wet.
If you get nothing, then there is a serious problem either in the windings,
or in the commutator end of the rotor.
If the generator is putting out above about 15 volts, but the system
wasn;t charging:
1. Leave the D and F generator terminals connected together, and slide the D
and F wires over their respective terminals. Remove the D lead from the
control box terminal, and connect the voltmeter between the D wire and a good
ground.
2. Repeat the start/run to 1000 rpm as above. Voltage should be the same as
it was at the generator.
No voltage means a break in the D wire. Shut down, allow to cool
reconnect the D wire to the D terminal at the control box. Next. remove the
F wire from the F terminal at the control and try again.
If you get good readings on both, the control box is bad.
To do a basic test the control box,
1. restore all gen wires and terminals to original non-jumpered state.
2. Remove A and A1 wires from the control box and jumper the two wires
together.
3. Neg meter lead to the D terminal (+ lead if neg ground) and other lead to
ground.
4. Start engine and slowly raise idle with a screwdriver or a wedge of wood.
When the voltmeter flickers then steadies, you should read somewhere between
15 and 17 volts depending on the outside temp. As I recall, the cooler it
gets, the higher the output voltage when it steadies. I have a temp to volts
chart in my toolbox. If the voltages don't match the air temp corrections,
then loosen the locknut on top of the regulator and turn it in to increase
the voltage and ccw to lower the voltage. Only turn the screw a tiny bit at a
time - like "2 or 3 minutes on the clock" and no more. Keep the revs
below 2500 or so to keep heat from affecting the regulator output.
The rest ofthe settings - cut in and cut out and mechanical clearances are
easy as a tune up, but you need a Glenns or a workshop manual to do it one
step at a time.
Mark Childers
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